we have to take L.C.M of 2, 3 & 4. these numbers are represented by 'n' in 'nth root a'
L.C.M of 2,3,4 is12.so we have to multiply 'n' with a number thus we get 12.
we can observe that 'n' is same for all numbers. now arrange them in ascending order based on inside numbers.
now, 12root3<12root4<12root6.then root3<3root4<4root6.